Telecommunications customers increasingly demand high-quality voice and data communications over cellular and wireless local area networks (LANs). Deployment of small cells in such LANs can give cell-splitting capacity gains. Thus, small cells are projected to become increasingly prevalent, as mobile network operators use these small cells to increase the capacities of their networks.
Due to their small coverage area, many small cells might be placed in close proximity to each other. Absent inter-network communication, those small cell networks might use the same time and frequency resources to transmit information. Granting users of these networks the same time-frequency resources can lead to interference, such as collisions.
In a dense deployment of small cells, co-channel interference between adjacent cells can be a limiting factor. Indeed, co-channel interference is the primary impediment in dense wireless networks, as out-of-band interference can be rejected using simple filtering.
Interference mitigation or rejection can improve signal reception in the presence of such interference. Specifically, co-channel interference can be mitigated using interference rejection combining (IRC). IRC uses spatial degrees of freedom (i.e., multiple antennas) at an Evolved Node B (also known as an eNodeB, an access point, or an AP) to exploit spatial covariance of the interference.
Conventionally, IRC assumes interference and a desired signal are synchronous (i.e., the interference is stationary). This assumption is highly idealized and might not be true in practice.
Further, in a dense wireless network, the exact properties of the spatial covariance of the interference might not be known at the point the signal is processed.